As discussed in blink-dev mailing list remove getPropertyShorthand and isImplicit from the Web expo…

Source/core/css/CSSStyleDeclaration.idl

 /*
  * Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 21 matching lines @@
     CSSValue           getPropertyCSSValue([Default=Undefined] optional DOMString propertyName);
     [TreatReturnedNullStringAs=Null, RaisesException] DOMString          removeProperty([Default=Undefined] optional DOMString propertyName);
     [TreatReturnedNullStringAs=Null] DOMString          getPropertyPriority([Default=Undefined] optional DOMString propertyName);
      [RaisesException] void setProperty([Default=Undefined] optional DOMString propertyName, 
                                     [TreatNullAs=NullString,Default=Undefined] optional DOMString value, 
                                     [Default=Undefined] optional DOMString priority);
 
     readonly attribute unsigned long    length;
     getter DOMString          item([Default=Undefined] optional unsigned long index);
     readonly attribute CSSRule          parentRule;
-
-    // Extensions
-    [TreatReturnedNullStringAs=Null] DOMString          getPropertyShorthand([Default=Undefined] optional DOMString propertyName);
-    boolean            isPropertyImplicit([Default=Undefined] optional DOMString propertyName);
 };